Thermal ground planes and light-emitting diodes

ABSTRACT

Methods and systems for thermal management of one or more LEDs are disclosed. One or more LEDs may be coupled with an external layer of a thermal ground plane according to some embodiments described herein. For example, the one or more LEDs may be electrically coupled with a circuit carrier with one or more electrically conductive traces etched therein prior to coupling with the thermal ground plane. The thermal ground plane may be charged with a working fluid and/or hermetically sealed after being coupled with the LED.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/926,057, filed Jan. 10, 2014, titled “THERMAL GROUND PLANES AND LIGHTEMITTING DIODES”, which is incorporated herein by reference in itsentirety.

BACKGROUND

It is well known that light-emitting diodes (LEDs) generate a lot ofheat that may adversely affect the performance and/or the reliability.Indeed, elevated junction temperatures have been shown to cause an LEDto produce less light (lumen output) and less forward current (or lessforward voltage). Over time, higher junction temperatures may alsosignificantly accelerate chip degeneration. Furthermore, high power LEDscan use significantly more power than a typical LED. Most of thisadditional power is converted to heat rather than light (about 70% heatand 30% light).

SUMMARY

Methods and systems for thermal management of one or more LEDs aredisclosed. One or more LEDs may be coupled with an external layer of athermal ground plane according to some embodiments described herein. Forexample, the one or more LEDs may be electrically coupled with a circuitcarrier with one or more electrically conductive traces etched thereinprior to coupling with the thermal ground plane. The thermal groundplane may be charged with a working fluid and/or hermetically sealedafter being coupled with the LED.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the presentdisclosure are better understood when the following Detailed Descriptionis read with reference to the accompanying drawings.

FIG. 1A illustrates a block diagram of a thermal ground plane accordingto some embodiments described herein.

FIG. 1B illustrates a block diagram of another thermal ground planeaccording to some embodiments described herein.

FIG. 2A illustrates a block diagram of a thermal ground plane accordingto some embodiments described herein.

FIG. 2B illustrates a block diagram of a thermal ground plane accordingto some embodiments described herein.

FIGS. 3A and 3B illustrate two examples of thermal ground planesaccording to some embodiments described herein.

FIG. 4 illustrates another example of light-emitting diodes formed on athermal ground plane according to some embodiments described herein.

FIG. 5 illustrates an example of a number of light-emitting diodesintegrated with a light-emitting diode according to some embodimentsdescribed herein.

FIG. 6 is a flowchart of an example process for placing LEDs on athermal ground plane according to some embodiments described herein.

FIG. 7 is a flowchart of an example process for placing LEDs on athermal ground plane according to some embodiments described herein.

FIG. 8 is a flowchart of an example process for placing LEDs on athermal ground plane according to some embodiments described herein.

FIG. 9 shows another example of an LED coupled with a thermal groundplane according to some embodiments described herein.

FIG. 10 shows another example of an LED and LED carrier coupled with athermal ground plane according to some embodiments described herein.

DETAILED DESCRIPTION

Embodiments described herein include one or more light-emitting diodes(LEDs) coupled with a thermal ground plane. Thermal ground planes workmuch like heat pipes in that they utilize phase transformation of aninternal working fluid to enable higher effective thermal conductivitythan is possible with a single material. In some cases, thermal groundplanes can increase thermal conductivity by an order of magnitude overconventional techniques. Thermal ground planes may include a thin,planar form allowing LEDs to be thermally bonded to an external surfacerather than on a standard LED substrate such as fiberglass-reinforcedpolymer or aluminum boards. The high thermal conductivity of a thermalground plane may allow LEDs to operate at higher power and/or greaterefficiency. In some embodiments, this may result in LED lighting devicesutilizing fewer LEDs to produce the desired lumen output. Better thermalconductivity may, among other things, improve an LED's life span and/orresult in a more consistent color output of an LED.

FIG. 1A illustrates a block diagram of a thermal ground plane 100according to some embodiments described herein. The thermal ground plane100 may have a thickness less than about 5, 2.5, 1.0, 0.75, or 0.5 mm.The thermal ground plane 100 may include a containment layer 102 and acontainment layer 106. The containment layer 102 and the containmentlayer 106 may enclose a liquid cavity 110 and a vapor cavity 108. Thecontainment layer 102 and/or the containment layer 106 may includecopper clad Kapton®, titanium, aluminum, copper, metal, compositematerial, polymer film, kapton, Pyralux®, polyimide film, alumina,polyethylene terephthalate (PET), a combination of the above, or anyother material. The containment layer 102 and/or the containment layer106, for example, may have a thickness of about 25-500 um.

The vapor cavity 108 may include a porous structure (e.g., athree-dimensional porous structure) that resists external pressure whileallowing internal vapor transport such that the vapor can easily moveaway from the heat source and condense at the heat sink. The vaporcavity 108 may include a woven mesh (e.g., a plain woven mesh) withopening sizes, for example, on the order of 0.5 mm and/or a thicknessless than 0.5 mm. As another example, the vapor cavity 108 may include apolyether ether ketone (PEEK) polymer material. As yet another example,the vapor cavity 108 may include mesh, foam, fabric or other porousmaterial made of ceramic, polymer, or metal.

In some embodiments, the liquid cavity 110 may include one or morewicking layers that may wick the condensed working fluid back to theheat source. In some embodiments, the wicking layers may utilizehydrophilic coatings for maximal passive fluid pumping performance. Theliquid cavity 110 may include, for example, a mesh or a woven mesh.Moreover, the liquid cavity 110 may also include micro channels etchedinto the containment layer 102 and/or the containment layer 106. Microchannels, for example, may be about 100 microns deep and 100 micronswide. The liquid cavity 110 may also include a micro porous foam,sintered metal, etc.

In some embodiments, the liquid cavity 110 may include a plurality ofpillars (or micro channels) that form a wicking structure on the innersurface of the containment layer 102. The pillars may be made fromtitanium, copper, aluminum, gold, composite material, nano-structuredtitania, titanium oxide, titanium, a composite of titanium with othermetals such as gold or copper, or other materials either alone or as acomposite The pillars may have, for example, a height of about 5-200microns, and a diameter of about 5-500 microns. The spacing between thepillars (i.e., the gap) can be about 1-500 microns. These dimensions ofthe pillars, e.g., height, diameter, and spacing (or gap), arecontrolled and optionally varied within the plurality of pillars withinthe thermal ground plane in order to maximize thermal ground planeperformance. For instance, the dimensions can be designed such thatviscous losses are minimized and capillary forces are maximized in orderto improve thermal ground plane performance. Although the dimensions, orcharacteristics, of the pillars can vary throughout the thermal groundplane, the characteristics can vary locally within the thermal groundplane or can vary from one pillar to another pillar, as desired for agiven application or use of the thermal ground plane. The pillars mayform all or part of the vapor cavity 108 and/or the liquid cavity 110.

A heat source 116 may be coupled with the containment layer 102. Theheat source, for example, may include a light-emitting diode. In someembodiments, the heat source 116 may be manufactured on the containmentlayer 102. As heat is generated by the heat source 116, the containmentlayer 102 and wicking structure transfer the heat to a working fluiddisposed within the liquid cavity 110. The working fluid may be anyfluid that has a latent heat of vaporization. The working fluid mayinclude water, mercury, sodium, indium, ammonium, acetone, ammonia,alcohol, and/or ethanol. The heat from the heat source 116 istransferred to the fluid, which isothermally transforms the fluid from aliquid phase into a vapor phase absorbing the latent heat ofevaporation. The evaporation of fluid from the wicking structure createsa region void of liquid in the wicking structure. This void of liquidcreates a capillary force through surface tension that draws liquidthrough the wicking structure, and allows vapor to be transported withinthe vapor cavity 108 as a result of a pressure gradient. The vaporcondenses and returns to a liquid state, thereby releasing the latentheat of evaporation at the location of condensation near a heat sink120. The liquid may be transported through the liquid cavity, which mayinclude a wicking structure, from the cooler region near the heat sink120 towards the hot region near the heat source 116, thereby completingthe thermal transport cycle.

Furthermore, the thermal ground plane 100 can be designed to transferheat out of the thermal ground plane 100, e.g., act as a cooling sourceat one area of the thermal ground plane 100. For example, the heat sink120 can act as a removal area of heat for a device attached in thatarea, and the heat source 116 can remove the heat transferred throughthe vapor cavity 108. In essence, the structure can transport thermalenergy in either direction, or act as a constant temperature source, fordevices attached to the thermal ground plane 100.

The thickness of the containment layer 102 can be varied to be thinnerat the location of the heat source 116 and thinner at the location ofthe heat sink 120, and thicker in other regions, which can be used forincreased heat transfer, as a mounting location or indicia for the heatsource 116, or other reasons, such as increasing structural integrity,as desired for the application of the structure. The varied thickness ofthe containment layer 102 can also facilitate thermal matching byreducing thermally-induced stresses imparted by the containment layer102 to devices mounted to the thermal ground plane. This relativelysmall thickness of the containment layer 102 can be supported by thickerbeams or pillars that extend from a first containment layer 102 to asecond containment layer 106 through the vapor cavity 108, if suchsupport is necessary for the given heat source 116. Further, a largerportion or the entirety of the containment layer 102 can be thinned toany desired thickness to increase thermal transfer, if desired orneeded, for a given application of the structure.

In some embodiments, the vapor cavity 108 may span most of or a majorityof the lateral dimension of the working portion of the thermal groundplane 100 and/or may take any form. In some embodiments, the vaporcavity 108 may have a depth of 10 microns to several millimeters, with anominal thickness of 100 microns to 1 millimeter. In some embodiments,the design of the wicking structure may allow for high mass flow ratesof the working fluid to be transported and thereby large amounts of heatto be transported. For example, large height and large spacing of thepillars will reduce viscous losses. In addition, smaller spacing of thepillars or smaller gaps in the mesh may increase capillary forces.Judicious choices of these parameters throughout the thermal groundplane 100 will provide optimum performance for a given application ofthe thermal ground plane 100.

In some embodiments, the pillars and/or mesh can be oxidized to formnano-structured titania, which can be used to increase wettability andthereby increase capillary forces, and enhance heat transfer, within thethermal ground plane 100.

In some embodiments, the heat source 116 and/or the heat sink 120 may becoupled with the same or opposite sides of the thermal ground plane 100.Moreover, the heat source 116 and/or the heat sink 120 may be coupled tothe containment layer 102 using any type of coupling such as, forexample, solder, thermal adhesive, thermal adhesive glue, thermaladhesive tape, conductive epoxy, thermal paste, etc.

In some embodiments, the thermal ground plane 100 may outperform heatpipes and/or vapor chambers. The thermal ground plane 100, for example,may have a thermal conductivity of greater than about 1,000 W/m-K, 1,250W/m-K, 1,500 W/m-K, 1,750 W/m-K, or 2,000 W/m-K. It can be noted thatthe thermal conductivity of solid copper is about 400 W/m-K, and solidaluminum is about 200 W/m-K. In some embodiments, a polymer-basedthermal ground plane according to embodiments described herein may havea heat flux of greater than 16, 18, 20, 22, 24, or 26 W/cm2, and ametal-based thermal ground plane according to embodiments describedherein may have a heat flux of greater than 120 W/cm2, 140 W/cm2, 160W/cm2, 180 W/cm2, etc.

In some embodiments, the thermal ground plane 100 may also include acontainment layer surrounding the thermal ground plane 100 andhermetically sealing the internal volume at a partial vacuum pressuresuch that the boiling point of the working fluid occurs at the optimaloperational temperature.

FIG. 1B illustrates a block diagram of another thermal ground plane 150according to some embodiments described herein. The thermal ground plane100 may have a thickness less than about 5, 2.5, 1.0, 0.75, or 0.5 mm.Thermal ground plane 150 is similar to thermal ground plane 100 exceptthe liquid cavity 110 is on both sides of the vapor cavity 108. Thethermal ground plane 150 may also have a heat sink 120 on thecontainment layer 106 rather than containment layer 102. The liquidcavity 110 may conduct condensed liquid from heat sink 120 to the heatsource 116.

FIG. 2A illustrates a block diagram of the thermal ground plane 100 withan LED 130 disposed on the containment layer 102 according to someembodiments described herein. In this embodiment, the thermal groundplane 100 is coupled with a circuit carrier 140 and one or more LEDs130. The circuit carrier 140 may include any type of material upon whicha circuit may be printed such as, for example, a copper layer on akapton layer. The copper layer may be partially etched and/or may be a1-oz copper layer. The kapton layer may have a thickness less than 500μm, 400 μm, 300 μm, 200 μm, 100 μm, etc. The kapton layer may include awhite or reflective coating.

The circuit carrier 140 may include various circuit elements such aspaths, connections, traces, resistors, transistors, capacitors,inductors, diodes, integrated circuits, etc. Circuit elements may besoldered and/or etched on the circuit carrier 140. For example, tracesmay be etched in the copper layer and/or electrical devices, such as theLED 130, may be soldered (using any soldering process such a solderreflow process) to the circuit carrier 140. In some embodiments, thecircuit carrier 140 may be bonded with the containment layer 102 usingany type of bonding process such as thermal adhesive, thermal adhesiveglue, thermal adhesive tape, etc.

In some embodiments, the LED 130 may be held at a specific operatingtemperature when coupled with the thermal ground plane 100. Thisoperating temperature may be determined based on the selection of theworking fluid and/or by setting internal thermal ground plane pressure.In some embodiments, the operating temperature may be below 100 C, 90 C,80 C, 70 C, or 60 C. Reducing the operating temperature of the currentstate of the art from 120 C may increase the efficiency of LEDs byapproximately 15%. In some embodiments, in use each individual LED usedwith a thermal ground plane may be operated at a higher current level,which may increase the luminous output of the LED and allow for areduced number of LEDs to produce a given luminosity. In someembodiments, the increased efficiency and increased current load foreach individual LED may enable use of approximately half the number ofLEDs in a given solid state light engine. Furthermore, the cost of thelight engine has a near one-to-one correlation with the number of LEDsused. The result may be a reduction in the solid state lightbulbmanufacturing expense by 50%.

In some embodiments, the circuit carrier 140 may not be included.Instead, the LED 130 and/or other circuit elements such as a copperlayer may be printed and/or soldered directly onto the containment layer102 (or the containment layer 106) either before or after the otherportions of the thermal ground plane are coupled together to form thethermal ground plane.

FIG. 2B illustrates a block diagram of the thermal ground plane 150 withan LED 130 disposed on the containment layer 102 according to someembodiments described herein.

FIG. 3A shows an example of a flexible thermal ground plane according tosome embodiments described herein. A flexible thermal ground plane, forexample, may achieve its greatest flexibility through the use of apolymer-based construction of the containment layers, which may includethin metal cladding for hermetically sealing the thermal ground plane.In some embodiments, higher levels of thermal conductivity and heat fluxmay be achieved with a rigid, metallic-based thermal ground plane asshown in FIG. 3B.

FIG. 4 illustrates an example of a number of LEDs 130 coupled with acontainment layer 102 of the thermal ground plane according to someembodiments described herein. As shown in the Figure, the LEDs 130 maybe electrically connected with each other or with other components viatraces 141 etched on the circuit carrier 140. The circuit carrier 140may be coupled with the containment layer 102 of the thermal groundplane. The traces 141 may conduct electrical power to the various LEDs130. The LEDs 130 may include an LED package, an LED on an LED carrier,a plurality of LEDs on a board, etc.

FIG. 5 illustrates an example of the LED 130 coupled with a thermalground plane 100 according to some embodiments described herein. The LED130 may be constructed on the circuit carrier 140. In some embodiments,the circuit carrier 140 may be illuminated and the LED 130 may beconstructed directly on the containment layer 102. A semiconductor die515 may be disposed on a heat slug 505. Alternatively, the semiconductordie 515 may be disposed directly on the circuit carrier 140 and thecontainment layer 102 with the use of the heat slug 505. Thesemiconductor die 515 may be any type of semiconductor chip such as, forexample, a gallium arsenide chip, an aluminum gallium arsenide chip, agallium arsenide phosphide chip, an aluminum gallium indium phosphidechip, a gallium(III) phosphide chip, a zinc selenide chip, an indiumgallium nitride, a silicon carbide chip, a silicon chip, an indiumgallium nitride chip, a boron nitride chip, an aluminum nitride chip, analuminum gallium nitride chip, an aluminum gallium indium nitride chip,etc. In some embodiments, more than one semiconductor die 515 may beincluded within the LED 130.

A bond wire 540 may provide a connection between an electrode 530 andthe semiconductor die 515. The electrode 530 may be used as anelectrical connection with the circuit carrier 140 and the semiconductordie 515. A resin mold 510 and/or an optical lens 520 may also beincluded. Various other components may be included. As shown in thefigure, one or more of the LED components may be coupled directly withthe thermal ground plane 100.

FIG. 6 is a flowchart of a process 600 for placing LEDs on a thermalground plane according to some embodiments described herein. The process600 starts at block 605. At block 605, traces can be etched into aportion of the circuit carrier 140. At block 610 LEDs and/or othercomponents may be placed on the circuit carrier 140. For example, one ormore surface mount LEDs and/or electrical components may be placed onthe circuit carrier 140. In some embodiments, an LED carrier with orwithout an LED may be placed on the circuit carrier 140. The LEDs and/orcomponents, for example, may be placed on the circuit carrier 140 usingsolder paste.

At block 615 the LEDs and/or other components may be soldered on thecircuit carrier 140 using such as, for example, a solder reflow processor the like. For example, during a solder reflow process, the circuitcarrier and/or components (including LEDs) may be raised to atemperature below 170° C., 180° C., 190° C., 200° C., 210° C., 220° C.,230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., etc.

At block 620 the circuit carrier 140 may be coupled with a containmentlayer of a thermal ground plane. For example, the circuit carrier 140may be coupled with the thermal ground plane using any process ormaterial known in the art such as, for example, thermal adhesive tapeand/or thermal adhesive glue. Blocks 605 and 610 may occur in any order.

FIG. 7 is a flowchart of a process 700 for placing LEDs on a thermalground plane according to some embodiments described herein. The process700 starts at block 705. At block 705, traces can be etched into aportion of the circuit carrier 140. At block 710 LEDs and/or othercomponents may be placed on the circuit carrier 140. For example, one ormore surface mount LEDs and/or electrical components may be placed onthe circuit carrier 140. In some embodiments, an LED carrier with orwithout an LED may be placed on the circuit carrier 140. The LEDs and/orcomponents, for example, may be placed on the circuit carrier 140 usingsolder paste.

At block 715 the LEDs and/or other components may be soldered on thecircuit carrier 140 using such as, for example, a solder reflow processor the like. At block 710, a thermal ground plane may be formed usingthe circuit carrier 140 as a containment layer of the thermal groundplane.

FIG. 8 is a flowchart of a process 800 for placing LEDs on a thermalground plane according to some embodiments described herein. The process800 starts at block 805. At block 805, traces can be etched into acontainment layer of a thermal ground plane. In this embodiment, thethermal ground plane may be constructed but not charged with a workingfluid and/or may not be hermetically sealed. At block 810 LEDs and/orother components may be placed on the containment layer. In someembodiments, an LED carrier with or without an LED may be placed on thecircuit carrier 140. For example, one or more surface mount LEDs and/orelectrical components may be placed on the circuit carrier 140. The LEDsand/or components, for example, may be placed on the circuit carrier 140using solder paste.

At block 815 the LEDs and/or other components may be soldered on thecontainment layer such as, for example, using a solder reflow process orthe like. At block 820 the thermal ground plane may be charged with aworking fluid and/or hermetically sealed. For example, during charging,air may be evacuated out of the thermal ground plane during charging. Asanother example, the working fluid may be placed within the thermalground plane during charging. The working fluid may be placed within thethermal ground plane at an elevated pressure below (or in someembodiments above) the ambient pressure. As yet another example, thethermal ground plane may be hermetically sealed during charging.Evacuate the chamber from having any non-condensable gases (possibly atan elevated temperature) and/or adding the working fluid to the liquidcavity and/or vapor cavity.

In some embodiments, the thermal ground plane 100 may be charged byplacing frozen working fluid (i.e., the working fluid in the solid phasestate) inside the thermal ground plane such as, for example by placingthe frozen working fluid between other layers of the thermal groundplane. Any remaining gases may also be evacuated from the thermal groundplane by introducing it to a vacuum.

Various other blocks may be included in any of the processes 600, 700,and/or 800. Moreover, any block may be omitted; and any of the blocksmay be performed in any order.

An LED (or multiple LEDs) may be coupled with a thermal ground plane ina number of different ways. FIG. 9 shows another example of the LED 130coupled with the thermal ground plane 100 according to some embodimentsdescribed herein. In some embodiments, the circuit carrier 140 mayinclude a via (or hole) 150 that is placed where the LED or the LEDcarrier is placed on the circuit carrier 140. In some embodiments, thevia 150 may be filled with thermal paste, conductive epoxy, thermaladhesive, copper, aluminum, etc. to conduct heat from the LED to thethermal ground plane.

FIG. 10 shows another example of the LED 130 and an LED carrier 135coupled with the thermal ground plane 100 according to some embodimentsdescribed herein. In some embodiments, the circuit carrier 140 mayinclude a via (or hole) 155 within which the LED 130 is placed. In thisconfiguration, the LED carrier 135 is coupled with the opposite side ofthe circuit carrier 140 as shown in FIG. 8 and the side of the circuitcarrier that is closest to the thermal ground plane. In this embodiment,the LED 130 and/or the LED carrier 135 may be more closely thermallyconnected with the thermal ground plane 100 and yet still haveelectrical connections through the circuit carrier 140.

A thermal ground plane that withstands a printed circuit board solderreflow cycle is also provided according to some embodiments describedherein. Typical solder reflow processes are performed at temperaturesaround 270° C. At this temperature the working fluid of the thermalground plane may expand and/or evaporate resulting in high pressureswithin the thermal ground plane. In some embodiments, a thermal groundplane may include one or more connections coupling the containment layer102 and/or the containment layer 106 internally through the vapor cavity108 and/or the liquid cavity. Such a thermal ground plane may be able tohandle internal pressures greater than 80 psi, 90 psi, 100 psi, 110 psi,120 psi, 130 psi, 140 psi, etc., without compromising the hermetic sealof the thermal ground plane and/or without releasing any of the workingfluid. Various types of connections or physical apparatus may be used.In some embodiments, the internal construction of the thermal groundplane may be redesigned in order to accommodate the new structurewithout significantly compromising performance.

Unless otherwise noted, as used herein, “LED” may include, for example,a semiconductor die that produces light, an LED package that includes asemiconductor die with at least a lens and/or a lead, multiplesemiconductor dies and/or leads in an assembly (an LED assembly), a oneor more semiconductor dies and/or leads on a board (chip on board)package.

Numerous specific details are set forth herein to provide a thoroughunderstanding of the claimed subject matter. However, those skilled inthe art will understand that the claimed subject matter may be practicedwithout these specific details. In other instances, methods,apparatuses, or systems that would be known by one of ordinary skillhave not been described in detail so as not to obscure claimed subjectmatter.

While the present subject matter has been described in detail withrespect to specific embodiments thereof, it will be appreciated thatthose skilled in the art, upon attaining an understanding of theforegoing, may readily produce alterations to, variations of, andequivalents to such embodiments. Accordingly, it should be understoodthat the present disclosure has been presented for purposes of examplerather than limitation, and does not preclude inclusion of suchmodifications, variations, and/or additions to the present subjectmatter as would be readily apparent to one of ordinary skill in the art.

That which is claimed:
 1. A method comprising: etching traces on acircuit carrier; placing one or more LEDs on the circuit carrier;soldering the one or more LEDs on the circuit carrier; and coupling thecircuit carrier with the containment layer of a thermal ground planeafter the soldering of the one or more LEDs on the circuit carrier. 2.The method according to claim 1, wherein the one or more LEDs are placedon the circuit carrier using solder paste.
 3. The method according toclaim 1, wherein the soldering the one or more LEDs on the circuitcarrier comprises heating the circuit carrier to a temperature below260° C.
 4. The method according to claim 1, wherein the circuit carrieris coupled with the containment layer of the thermal ground plane usinga thermal adhesive.
 5. A method comprising: etching traces on a circuitcarrier; placing one or more LEDs on the circuit carrier; soldering theone or more LEDs on the circuit carrier; and thereafter, forming athermal ground plane using the circuit carrier as an external layer ofthe thermal ground plane.
 6. The method according to claim 5, furthercomprising hermetically sealing the thermal ground plane.
 7. The methodaccording to claim 5, further comprising charging the thermal groundplane with a working fluid at a reduced pressure relative to ambient. 8.The method according to claim 5, wherein the one or more LEDs are placedon the circuit carrier using solder paste.
 9. The method according toclaim 5, wherein the soldering the one or more LEDs on the circuitcarrier comprises heating the circuit carrier to a temperature below260° C.
 10. A method comprising: etching traces on a containment layerof a thermal ground plane; placing one or more LEDs on the containmentlayer of the thermal ground plane; soldering the one or more LEDs on thecontainment layer of the thermal ground plane; and thereafter, chargingthe thermal ground plane with a working fluid.
 11. The method accordingto claim 10, wherein charging the thermal ground plane further comprisesplacing fluid within the thermal ground plane at a pressure less thanambient pressure.
 12. The method according to claim 10, wherein chargingthe thermal ground plane further comprises placing fluid within thethermal ground plane at a pressure greater than ambient pressure. 13.The method according to claim 10, wherein charging the thermal groundplane further comprises hermetically sealing the thermal ground plane.14. The method according to claim 10, wherein the one or more LEDs areplaced on the thermal ground plane using solder paste.
 15. The methodaccording to claim 10, wherein the soldering the one or more LEDs on thecircuit carrier comprises heating the circuit carrier to a temperaturebelow 260° C.
 16. A lighting device comprising: a thermal ground plane;and an LED package disposed on the thermal ground plane.
 17. Thelighting device according to claim 16, further comprising a circuitcarrier coupled with the LED and the thermal ground plane.
 18. Thelighting device according to claim 17, further comprising the circuitcarrier coupled with the LED and the thermal ground plane, wherein thecircuit carrier includes one or more electrically conductive traces. 19.The lighting device according to claim 16, further comprising thecircuit carrier coupled with the LED and the thermal ground plane,wherein the circuit carrier is a flexible circuit carrier.
 20. Thelighting device according to claim 16, wherein the thermal ground planecomprises a containment layer, a vapor cavity, and a liquid cavity. 21.The lighting device according to claim 16, wherein the thermal groundplane comprises a liquid wicking layer.
 22. The lighting deviceaccording to claim 16, wherein the thermal ground plane comprises one ormore mesh layers.
 23. The lighting device according to claim 16, furthercomprising a copper layer that includes a plurality of electricallyconductive traces disposed on a polymer film layer.
 24. The lightingdevice according to claim 16, wherein the thermal ground plane comprisesa containment layer, and wherein the LED comprises a semiconductor diedisposed on the containment layer.